Inflammatory bowel diseases, such as Crohn's disease or ulcerative colitis cause inflammation of the gastrointestinal tract, most commonly the small intestine, with resulting abdominal pain, difficulty in digesting food, and other symptoms. Clinically diagnosing Crohn's or ulcerative colitis is an expensive, time consuming process which often requires some form of anesthesia. Generally, such diagnosis is made by performing an endoscopy, colonscopy, sigmoidoscopy or radiological technique which often must be done in a hospital or clinic-like setting and sometimes requiring a biopsy of apparently affected tissue. It is estimated that at least one million Americans have Inflammatory Bowel Disease (IBD), with about 50% having Crohn's disease and about 50% having ulcerative colitis. Because of health care costs and diagnostics, the actual estimated number of patients with IBD may be significantly higher. Therefore it would be highly desirable to have a diagnostic test that is less invasive, less expensive and can accurately identify those patients with MAP infection. Ultimately, treatment with appropriate antibiotics will go a long way toward relieving them from the disease.
Based on the clinical similarities of animals infected with paratuberculosis, early research suggested that the disease which came to be known as Crohn's disease was caused by mycobacteria Early studies on Crohn's disease did not detect MAP in tissues from patients with Crohn's disease by conventional staining and culture techniques because such patients may have mycobacterium which are cell-wall deficient, and because of the difficulties in cultivating MAP, with its slow growing characteristics. A research group at Baylor College of Medicine patented the discovery of p36 (a protein from MAP) for serologic detection of MAP antibodies from Crohn's patients in U.S. Pat. No. 5,776,699. Researchers have also recently utilized the insertion element IS 900 to accurately identify MAP (Mishina, D Katsel, P Brown, S t Gilberts, E C Greenstein R J “On the Etiology of Crohn Disease” Proc Natl Acad Sci USA 1996, 93: 9816-20.) and others have found MAP in tissue and breast milk samples from lactating mothers with Crohn's disease (D. Schwartz et al., “Use of short-term culture for identification of Mycobacterium avium subsp paratuberculosis in tissue from Crohn's disease patients” Clin Microbiol Infect 2000: 6, 303-307. Naser, S A Schwartz, D. Shafran, I, “Isolation of Mycobacterium avium subsp paratuberculoisis from breast milk of Crohn's disease patients” Am Jl Gastroenterol 2000, 95:1094-5.
At the present time, however, no one has provided a method for diagnosing Crohn's disease that is caused by MAP (there may be other etiologies for Crohns or irritable bowel syndrome other than MAP) using a simple blood test. This blood test can also be used to identify Crohn's disease patient population with MAP infection. Additonally, this novel blood test can be used to differentiate IBD patients with MAP infection from those without MAP infection. Moreover, such tests can be used to monitor and evaluate treatment after obtaining a first positive result. Repeat blood tests can determine if the bacterium is being reduced or eliminated from the system, or not.